Metal solubility enhancing peptides derived from barley protein

Area of Science:

• Nutritional Biochemistry
• Food Science and Technology

Background:

• Mineral bioavailability is crucial for human health and is directly linked to their solubility in physiological fluids.
• Dietary protein hydrolysates are explored for their potential to improve mineral absorption.
• Barley protein, specifically hordein, is a potential source for such hydrolysates.

Purpose of the Study:

• To investigate the metal-binding capacity of barley protein hydrolysates and their purified fractions.
• To quantify the enhancement in solubility of various metal ions (Fe2+, Fe3+, Ca2+, Cu2+, Zn2+) in the presence of these hydrolysates.
• To elucidate the mechanisms underlying the metal-binding interactions.

Main Methods:

• Preparation and fractionation of barley protein hydrolysates.
• Incubation of hydrolysates with specific metal ions (Fe2+, Fe3+, Ca2+, Cu2+, Zn2+).
• Quantification of metal ion solubility using spectrophotometric methods.
• Analysis of peptide composition and structural interactions.

Main Results:

• Barley protein hydrolysates demonstrated a significant increase in the solubility of metal ions, ranging from 10-fold for Ca2+ to 118-fold for Fe2+.
• Low molecular weight peptide fractions exhibited the most effective metal ion binding.
• Synergistic effects involving electrostatic, coordination, and hydrophobic interactions were identified as key mechanisms for metal ion stabilization.

Conclusions:

• Barley hordein hydrolysates possess substantial metal-binding capacity, enhancing mineral solubility.
• These hydrolysates show promise as functional ingredients in dietary supplements to improve mineral bioavailability.
• The combined charged and hydrophobic residues in peptides are critical for effective metal ion chelation.